Defensive IFR – The Importance of a Two Way Relationship

December 28th, 2010

The following has been abbreviated from an article was posted on avweb, the original article can be found at This article originally appeared in Aviation Safety, Feb. 2005.

The article illustrates the importance of a two way relationship between pilot and controller. It may be the controller’s responsibility to provide you with separation in most IFR situations, but this does not absolve you of the final ultimate responsibility for the safe conduct of the flight. Questioning or cross checking clearances is not argumentative or disruptive it is part of your legal responsibility as a pilot, and any ATC who is worthy of having his posterior in the seat will recognise this and appreciate it.

“The irony of all this is that it’s your chair moving at 150 knots (ed-or more!), not the controller’s. When your airplane slams into that unseen ridge, he’ll probably feel really bad. You probably won’t feel a thing.”

Defensive IFR

July 30, 2007
by Bart Epstein

Why Readbacks Are Important

Reading back a clearance is important not only to make sure you and the controller are on the same page, but to ensure the clearance you read back is actually for you. The “party-line” nature of ATC communications with aircraft sometimes means that transmissions are blocked and similar-sounding callsigns are really meant for someone else. As discussed in the main text below, a crew complied with a descent clearance for another aircraft. Although the wrong crew read back the clearance, the controller didn’t catch the error.


Controllers are just like pilots: All are human and make mistakes. Most are good, know the rules, do everything they can to make your flight efficient and safe, and make sensible judgments. Only a tiny fraction are highly paid chair-warmers too lazy or bored to have opened the book (FAA Order 7110.65) for a refresher on the finer points of their craft.

For pilots, what this means is that amidst what is overwhelmingly professional and courteous ATC service, you’ll hear the occasional boneheaded clearance, instruction or suggestion with which no sensible pilot should comply. That’s why we have readback procedures and is one of the reasons the word “unable” exists and why you should use it without fear of retribution when necessary or appropriate.

Trust, But Verify

The image depicts the minimum vectoring altitudes (circled in red) for the San Diego TRACON overlaid on the area en route IFR low-altitude chart. The accident occurred just southeast of the JLI VORTAC.

No better recent example can be found to illustrate the point that it’s your butt on the line than on May 10, 2004, when Piper Seminole N304PA collided with terrain near the Julian, Calif., VORTAC (JLI) and was destroyed. Both pilots aboard the twin were killed. The planned flight was from Phoenix, Ariz., to Carlsbad, Calif. Nighttime visual conditions prevailed, although the flight was operating on an IFR flight plan.

The cleared routing for N304PA was: Gila Bend, V66, Imperial, V458, Julian, then direct to Palomar. N304PA was number four in a train of five airplanes flying the same route for training. The airplanes were separated by about five to 10 minutes. The airplane directly ahead of N304PA was N434PA, another Seminole.

According to the NTSB, ATC communications and radar data show that N304PA reported level at 8000 feet MSL to the San Diego North Radar (SDNR) controller at 2043:48. The SDNR controller instructed the pilot to fly a 260-degree heading after crossing JLI and then intercept the Palomar localizer. The pilot read back the clearance. At 2045:47, the SDNR controller told the pilot of N434PA to descend to 6000 feet. The pilot of N434PA acknowledged the clearance. At 2047:55, the SDNR controller transmitted, “Seminole four papa alpha descend and maintain five thousand two hundred.” The pilot of N304PA responded, “Down to five thousand two hundred for three zero four papa alpha.” According to the controller, this clearance was intended for N434PA. The controller did not recognize that the clearance had been acknowledged by N304PA rather than N434PA. At 2052, the San Diego AFSS contacted the SDNR sector reporting that they were receiving a strong ELT signal from near the JLI Vortac.

Why the controller missed the readback from the wrong airplane is anyone’s guess. And, certainly, better situational awareness on the part of the two pilots aboard the Seminole probably would have prevented this accident. But the point is that once you close the cabin door and the wheels leave the ground, you’re mostly on your own to ensure the wheels safely touch down again.

Little Voices

Anytime you’re not flying straight and level well above terrain, the little voice in your head should be asking yourself some basic questions: Where am I going? Where am I going after that? What altitude should I be at now? The next leg? What am I going to do if this doesn’t work out?

For example, let’s say you’re droning along en route to your destination when you become aware the weather there has gone down the tubes. At the least, you need to stop and get some more fuel with which to tackle the weather, so you tell ATC you’d like to divert to nearby Cowpie County International. You request a “vector and lower” and the TRACON controller you’re handed off to makes a transposition error on your altitude. He meant to set you up to join the feeder route for the VOR approach at 5300 feet, but instead tells you to “descend and maintain 3500 until established” and clears you for the approach. You read back the clearance and grab the approach plate to get your bearings.

Will you notice that the altitude you’ve been given does not match the feeder route? Will you see that the altitude to which you’re descending is below the minimum safe altitude (MSA) circle on the plate?

A little voice in your head should be asking if you’re where you should be for the approach. That’s one of the reasons why each published feeder route has a minimum altitude and the plate itself has the MSA information.

Twice I have received clearances that made no sense. Both times I was glad my instrument instructor drummed into me the need to physically trace my entire route on a map before takeoff. One of the bad clearances was actually to a fix over the Atlantic Ocean. I still remember sitting in my plane that night, wondering what I had written down wrong to think I was cleared out over the water.

After conferring with the tower, I shut down the engine, trekked up to the tower cab and sat down with the controller to trace out my clearance on a chart. He was positively stunned, especially since he’d given out that same clearance more than 1000 times without any problems. Apparently, the TRACON or someone down the line always amended those clearances well before they became a problem. And, to date, no one had to implement lost comm procedures while flying the bad clearance.

Know Your Rights

But how many pilots would do the same? How many are willing to analyze an ATC clearance or directive on-the-fly then stand up on two hind legs and refuse an unsafe or out-of-line instruction?

Part of the problem is that we tend to accept the authority of anything uttered by a controller as the last word. After all, he wouldn’t be a controller if he didn’t know what he was doing, right?

The antidote, of course, is knowledge and experience. The knowledge comes from knowing the FARs and AIM procedures; we can assure you most controllers and pilots don’t. Experience comes from flying and using the system and applying that knowledge.

And that’s why an annual flight review or IPC without some discussion of real-world procedures and regs is a sham, lending truth to the notion that what you don’t know can hurt you.

Am I Paranoid Enough?

Some may say it is not practical to be constantly paranoid and suspicious of everything ATC asks or commands. And it may seem like overkill to focus on these types of errors when so many pilots are still making much larger and dumber mistakes, like flying well below an MDA to take a peek or launching into icing conditions with nothing more than a lukewarm pitot tube.

Of course, flying defensively is about more than nitpicking clearances. At the end of the day, it’s your butt that matters, not the controller’s.

Controlling The Negotiation

By Jeb Burnside

On many of my regular flights up from the southeast, controllers at the local TRACON routinely give me a descent clearance many miles out from my destination. I suspect it’s because I’m in a FLIB and their letters of agreement specify that IFR FLIBs must be at 5000 feet many miles south of my home plate’s feeder fix. But there are numerous airports in that area, generating all kinds of traffic, and radio reception is sometimes is lacking at that altitude in that area. Droning along level at 5000ft for many minutes that far out from my destination gives me the willies, as I know that, eventually, someone is going to get in my way. Over the years, a few encounters of the close kind with aircraft not talking to the TRACON confirmed my fears.

So, I generally try to negotiate something other than that clearance, usually to cross 20 miles southwest of the fix at and maintain 5000 feet. That keeps me higher longer and ensures decent communications. No one seems to mind.

On other occasions, I’ve refused heading changes and climbs or descents while in the en route environment if they would put me in ice, tall cumulus clouds or other bad situations.

Putting aside for the moment the misconception that controllers “control” airplanes, the bottom line — for me, anyway — is that dealing with ATC is a negotiation. If I like the way the negotiation is going, I’ll be quiet. If there’s a safety, comfort or operational reason for me to not like things, I’ll renegotiate with the controller. I’ll do it professionally, calmly and concisely, and I won’t hesitate to tell him what the problem is. Ninety-nine percent of the time, we can work out something with which we both can live. Especially me.

Who’s The Boss?

By Jeb Burnside

The irony of all this is that it’s your chair moving at 150 knots, not the controller’s. When your airplane slams into that unseen ridge, he’ll probably feel really bad. You probably won’t feel a thing.

Maybe it’s the anarchist gene in me, but I’m not spring-loaded to believe everything the government — or a controller — says. Yet as pilots, most of us react in the opposite way when confronted with ATC clearances and instructions that disrupt our plans and sound fishy or ill-advised. We go along. We comply. We’re happy to help.

Why? For the simple — and understandable — reason that we assume controllers know their business and, as only sometime-users of the system, we similarly assume our knowledge is flawed. So we go along with ATC’s wishes, sometimes to a fault.

The ultimate authority, of course, is FAR 91.3, the PIC imprimatur that gives you ultimate authority over the safety of the flight. Controllers don’t exactly have their own version of this and even if they did, your authority trumps ATC’s.

On the other hand, there’s FAR 91.123, which requires compliance with ATC instructions and directives and requires the pilot to seek clarification if he doesn’t understand ATC’s wishes. The ultimate escape valve, of course, is emergency authority, which overrules anything ATC has to say.

If it was this simple, though, rejecting clearances would be easy. Instead, there are massive gray areas here. For example, rejecting a directive to land your Skyhawk short behind a landing 737 and opting instead to land long for wake avoidance reasons might screw up the local controller’s flow, but that’s not your problem. No right-thinking ATC facility would make an issue of it. The same applies when given a clearance for an immediate takeoff? Should you rush your takeoff and departure routine just because it might save two minutes?

Putting the shoe on the other foot, suppose you were following another aircraft to land, the tower controller calls for a go-around and you reply, “Unable.” You certainly have the authority to do so but you’d better have a good explanation at hand, such as a rough engine, smoke in the cockpit or some other emergency-like condition. The FAA will take a dim view of promiscuous use of “unable” and we suspect an administrative law judge will know the difference between legitimate PIC balking and pure bs.

Some of what ATC does falls into the realm of “suggestions.” Comply at your own whim and risk. Refusing the request won’t cost you any enforcement points while granting it could cost a lot more.

Cessna Training Manuals

I had to Learn About Flying from That!

December 24th, 2010

When I was a student pilot, I used to love reading a column in one of the popular aviation magazines (\’Flying - called \”I Learned About Flying from That\”.

I guess many other pilots enjoyed the column, the column is still going and has been published in book form. The attraction was learning about stupid situations others had unwittingly got themselves into, and narrowly – typically by absolute luck – escaped, in the hope of avoiding these situations yourself.

Articles are personal accounts, and normally anonymous, and as with CAHRS (which are also a great read for all pilots), the column permits the author to write freely in a format that is extremely helpful to others.

I\’ve received recently a few similar accounts, and so named the blog series \”I had to Learn About Flying from That\’, as a reference to the great magazine articles, and as a slight deviation on the theme, in an attempt to remind ourselves that we have (I hope!) progressed a great deal from the days that flying was trial and error, and there are many avenues available to prevent you getting into these situations if you pay attention.

The following is a story by a pilot who had to learn the hard way, in his words.

C of G Limits

So…..there we were….in a far away land of wooden curios and Carlsberg beers (greens)….with a C210 …..six up…baggage…fuel and ….wooden curios….all wanting to get back home….which was 6 hours flying time and two stops away.
How do we solve this problem of space/weight/fuel and still get everyone home without leaving anything behind….was what my friend and I found ourselves discussing on a sidewalk in a dusty African City in Central Africa
He had a Be58 Baron to load and I a C210…. All the wooden curios pushed the weight over the all up weight limit and so a compromise had to be found….so we calculated the flying time for the first leg which turned out to be fairly short…a mere 2h20……for a C210 that equates to roughly 140 litres…add some for mum and make it 200 litres….which means we have about 180 litres of weight available …roughly 160kg…GREAT …problem solved…..
When I walked the pax to the plane I noticed the tail was very near the ground and the nose wheel oleo rather stretched….okay I thought…load the front pax first and the rear last….that worked a charm and then when I started the engine the propwash pulled the nose down and all appeared fine….so off we taxi and trundle to the holding point. Take-off is fine and the climb to altitude is fine…level off and we go cruising along at 150kts….start the descent…fuel is still good although the gauges are extremely close to the big E but I`m expecting that cause of the calculated fuel which means there should only be about 60 litres in the tanks….30 a side….hence the almost empty gauge.
Everything is going smoothly and I round out for the flare….throttle to idle and….and…..wheeyyy….she sits on her butt ….and those spring steel undercarriage legs bounce us back up again….and I push forward on the stick cause the nose is way high….and pull back as we come down again….and those spring steel legs do there thing again…with more enthusiasm…..and again I push forward and pull back as we come down….and again we are flung into the air….much higher this time…and much slower….the elevator and wings are losing effectiveness…the thought enters my mind that if we hit again…something will break….and so instead of pushing forward I hold it sort of straight and level and firewall the throttle….and we sink back towards the runway and touch fairly softly….nose high and then I push the nosewheel down and close the throttle….and then only notice we`ve used up half of a 4000m runway bringing the beast back under control.
Its rather quiet in the plane as we taxi to the apron….

I never took into account the movement of the C of G with the fuel burn….it moved even further back than its limit at take-off….and when I closed the throttle on landing…it did what nature wanted it to do…sit on its butt.

Thank goodness for a long runway, some natural instinct, and that there was no engine failure in a critical stage ….it would have been nasty.

And the moral of the storey? Weight and balance calculations are taught for a reason, not just to irritate student pilots during ground studies!


There are many resources available to prevent you needing to learn the hard way. A considerable amount are free online resources, others are part of your basic training which will be missed if you don\’t complete homework, and some are books which are not more than a few USD, most importantly they are all a thousand times cheaper than an accident, and at least on tenth of a flying hour on most aircraft.

The major investment required in most training and preparation avenues available for improved safety is your time, and considering the return on investment – that is, reducing your own and your passengers risk of loosing their lives, isn\’t it surprising how few people want to invest?

If you carry on reading, you\’ve probably committed to the first step towards improving your own airmanship, do your passengers and all of us involved in aviation a favour, and keep it up.

Deer on the Runway

December 11th, 2010

I found this on

I’ve heard it before, but it’s not been posted here before. As for myth busters, again I am really sure this happened somewhere to someone, if not more than once….so enjoy!

CFI and his Student are holding on the runway for departing cross traffic when suddenly a deer runs out of the nearby woods, stops in the middle of the runway, and just stands there looking at them.

Tower: Cessna XXX cleared for take-off.
Std: “What should I do? What should I do?”
Inst: “What do you think you should do?”
Std: “Maybe if I taxi toward him it’ll scare him away.”
Inst: “That’s a good idea.”
(Taxi toward deer, but deer is macho, and holds position.)
Tower: Cessna XXX cleared for take-off, runway NN.
Std: “What should I do? What should I do?”
Inst: “What do you think you should do?”
Std: “Maybe I should tell the tower.”
Inst: “That’s a good idea.”
Std: Cessna XXX, uh, there’s a deer down here on the runway.
(long pause)
Tower: Roger XXX, hold your position. Deer on runway NN cleared for immediate departure.
(Two seconds, and then — by coincidence — the deer bolts from the runway, and runs back into the woods.)
Tower: Cessna XXX cleared for departure, runway NN. Caution wake turbulence, departing deer.

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